Containment of dust and fumes from a metallurgical vessel

Claim 3

The device of claim 1 including means for synchronizing the partial restriction of said hood mouth with the rotation of said furnace from its upright position.

Claim 4

The device of claim 1 wherein said means comprises a plate.

Claim 5

The device of claim 3 wherein said plate is protected from heat.

Claim 6

The device of claim 3 wherein said plate is cooled with a fluid.

Claim 7

The device of claim 3 wherein said plate is cooled with water.

Claim 8

The device of claim 1 wherein said means is external of said hood.

Claim 9

The device of claim 1 wherein said means is capable of moving with respect to the thermal movement of said hood so that the distance between said means and said hood is constantly maintained.

Claim 10

The device of claim 1 wherein said metallurgical furnace is a basic oxygen furnace.

Claim 11

The device of claim 1 wherein said means is capable of partially restricting the cross-sectional area of said hood mouth in proportion to the degree of rotation of said furnace from its upright position.

Claim 16

The device of claim 12 including means for synchronizing the partial restriction of said hood mouth with the degree of misalignment of said furnace mouth and said hood mouth.

Claim 17

The device of claim 12 wherein said means comprises: a. a pair of parallel tracks fixed adjacent to said hood lying in a common plane that extends adjacent to and beyond said hood mouth; b. a movable plate that is carried by said tracks; and c. means for moving said plate from a position remote from said hood mouth to a position adjacent to said hood mouth in partial restriction thereof.

Claim 18

The device of claim 14 wherein said tracks carry means for protecting said tracks from heat and molten metal.

Claim 19

The device of claim 14 wherein said moving means comprises: a. a pair of motors each of which is mounted on said plate at the sides thereof; and b. a drive wheel being carried by each of said tracks being rotatably fixed to each of said motors for moving said closure plate along said tracks; each of said motors being synchronized with each other.

Claim 20

The device of claim 14 wherein said driving means comprises: a. a motor situated at the remote end of and between said tracks; b. a drive axle cooperatively associated with said motor and extending between said tracks; c. a pair of first sprocket wheels one of which is mounted to one end of said drive axle and the other of which is mounted to the other end of said drive axle; d. a pair of second sprocket wheels disposed at the other opposite end of said tracks, one of which is cooperatively associated with one of said first sprocket wheels and the other of which is cooperatively associated with the other of said first sprocket wheels. e. a pair of continuous chains engaging each pair of cooperating first and second sprocket wheels; and, f. a pair of cog wheels fixed to each side of said plate, one of which is cooperatively associated with one of said continuous chains and the other of which is cooperatively associated with the other of said continuous chains.

Claim 21

The device of claim 14 wherein said driving means comprises: a. two cylinders each of which is pivotedly mounted to a frame at the remote end of said tracks; b. each cylinder carrying a plunger rod having its free end pivotedly mounted to said plate; and, c. means for activating said plunger rods for extension and retraction.

Claim 22

The device of claim 14 including expansion mechanisms for moving said tracks with respect to said hood mouth to accommodate the thermal expansion of said hood so that the distance between said plate and said hood mouth is constantly maintained.

Claim 23

The device of claim 19 wherein said expansion mechanisms comprises: a. a cylinder secured to a frame; b. each cylinder having a plunger rod that is secured to said tracks; and c. means for activating said plunger rods for extension and retraction.

Claim 24

In an exhaust hood having a hood mouth that cooperates with a rotatable metallurgical furnace having a furnace mouth and being adapted to rotate about an axis in a clockwise and a counter-clockwise direction; said hood mouth having a centerline perpendicular to the plane in which said hood mouth lies and said furnace mouth having a centerline perpendicular to the plane in which said furnace mouth lies; said centerlines being coaxial when said furnace is disposed in a position for oxygen blowing operations and said centerlines intersecting each other at an angle when said furnace is rotated clockwise or counterclockwise, wherein the improvement comprises: Means for use at said hood mouth that is capable of moving into a position adjacent to said hood mouth that partially restricts the cross-sectional area of said hood mouth to provide a reduced unrestricted portion having a centerline that is perpendicular to the plane in which said reduced unrestricted portion lies and that is substantially parallel to said centerline of said hood mouth; said centerline of said reduced unrestricted portion being displaced from the centerline of said hood mouth in the same direction as the centerline of said furnace mouth when said furnace is rotated, the displacement of said centerline of said reduced unrestricted portion being proportional to the said angle whereby the face velocity of gas effluents entering said hood through said reduced unrestricted portion is increased to improve the gas effluent capture efficiency of said hood.

Claim 25

In an exhaust hood having a hood mouth that cooperates with a rotatable metallurgical furnace having a furnace mouth and being adapted to rotate about an axis in a clockwise and a counter-clockwise direction; said hood mouth having a centerline perpendicular to the plane in which said hood mouth lies and said furnace mouth having a centerline perpendicular to the plane in which said furnace mouth lies; said centerlines being coaxial when said furnace is disposed in a position for oxygen blowing operations and said centerlines intersecting each other at an angle when said furnace is rotated clockwise or counterclockwise, wherein the improvement comprises: Means for use at said hood mouth that is capable of moving into a position adjacent to said hood mouth that partially restricts the cross-sectional area of said hood mouth to provide a reduced unrestricted portion having a centerline that is perpendicular to the plane in which said reduced unrestricted portion lies and that is substantially parallel to said centerline of said hood mouth; said centerline of said reduced unrestricted portion being displaced from the centerline of said hood mouth in the same direction as the centerline of said furnace mouth when said furnace is rotated, the displacement of said centerline of said reduced unrestricted portion being proportional to the said angle whereby the face velocity of gas effluents entering said hood through said reduced unrestricted portion is increased to improve the gas effluent capture efficiency of said hood.